I'm trying to write a simple wavefront obj decoder and I have come to a block. Here's a sample from my obj file:
Quote:
#384 vertices, 764 faces
v 0.81895431 0.99238976 -0.81895431
v 0.88494427 0.96555492 -0.81914344
...
..
vt 0.26794330 0.59115951
vt 0.26829364 0.59066995
...
..
vn 0.28871099 0.91284825 -0.28871099
vn 0.45619804 0.84870605 -0.26754697
...
..
f 1/55/1 381/56/381 2/49/2
f 2/49/2 4/51/4 1/55/1
...
..
Where I'm having issue is in understanding what to do with the last two lines for rendering. Obj files define the last two lines like so: f v0/vt0/vn0 v1/vt1/vn1 v2/vt2/vn2, where v=vertext, vt=vertex texture coord, vn=vertex normal.
When my arrays match in their indexes (i.e. v0=vt0=vn0, v1=vt1=vn1, v2=vt2=vn2), I can efficiently draw them like so:
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_NORMAL_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glVertexPointer(3, GL_FLOAT, 0, vertex_array);
glNormalPointer(GL_FLOAT, 0, normal_array);
glTexCoordPointer(2, GL_FLOAT, 0, texture_array);
glDrawElements(GL_TRIANGLES, vert_and_norm_size, GL_UNSIGNED_BYTE, index_array);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
glDisableClientState(GL_NORMAL_ARRAY);
glDisableClientState(GL_VERTEX_ARRAY);
But my Object file only has the vertex array and vertex normal array matching in their indexes, and the texture coord array has different indexes:
f 1/55/1 381/56/381 2/49/2
f 2/49/2 4/51/4 1/55/1
So the above code snippet won't work because "index_array"'s indexes won't match for the texture array. So my question is this: How can I best render my object when the indexes of my arrays aren't the same? Is there a methodology in opengl that I can have multiple index arrays, one for my vertex array, normal array, and texture array?
Or something completely different altogether?
